Field of the Invention
A sediment control device is used to intercept sediment-laden stormwater runoff and to remove the sediment that would otherwise pollute downslope areas and waterways. More particularly, the device includes a frame and a filtering fabric with two filtering surfaces.
Prior Art
Sediment laden stormwater runoff from construction sites is a major contributor to pollution of waterways and receiving bodies of water. The common practice is to treat stormwater runoff from construction sites by installing silt fences around the perimeter of the site and along downstream portions of the site to retain the sediment on-site. Silt fences are often ineffective at controlling sediment loss from sites due to a number of factors including: improper design, improper installation and maintenance or the ineffectiveness of the silt fence device itself. In many cases, the silt fence fabric does not allow proper filtration or becomes clogged and rather than filter stormwater, the stormwater is ponded behind the silt fence causing disruption of the drainage patterns which can lead to further soil erosion, transport of sediment and increased downstream pollution. Another shortcoming of current devices is that they must be removed and replaced during various phases of construction to allow for construction access, leaving the construction sites unprotected.
A typical silt fence consists of a synthetic filter fabric (geotextile) stretched between wooden or metal fence stakes along horizontal control level. The stakes are installed on the downhill side of the fence and the bottom edge of the fabric is trench into the soil and backfilled on the uphill side. The stormwater slowly passes through the fence while depositing the sediment on the uphill side of the fence. Stronger silt fences are created by reinforcing the filter fabric with a wire mesh backing
Another product that is utilized is a sediment filter sock or tube. These devices consist of a tube or sock of permeable netting with an inner core of synthetic or organic filter material. These devices are typically placed In a slight depression that is formed in the ground and secured with wood or metal stakes that are driven through the tubes or are driven behind the tubes and connected to the tubes with wire, ropes or similar devices. Much like typical silt fences these filter socks or tubes can be ineffective due to typical poor flow-through characteristics and difficulties associated with ineffective installations.